My daughter is going to get corticosteroid injection in her knees and ankles and rheumo says she can't play or go to school 2 days after. why?

So the medication : So the corticosteriod injection can take effect.

Steroids can : Potentially cause some weakness of soft tissue structures. May not want child to overdo playing where may potentially cause injury. May be concerned over a steroid flare as well. Don't be afraid to ask the doc himself ...Your question is a good one which the doctor should answer for you....